In recent years, there has been considerable interest in generating and disseminating information about health care quality. However, it remains unclear whether quality information has an impact on consumers' knowledge, behavior, or satisfaction. This study will: (1) identify factors associated with consumers' use of employer-disseminated information about health plan and medical group performance, (2) determine and how consumers use such information open enrollment, (3) use qualitative quality, but then base their decisions largely on price, (4) design and implement an intensive program for disseminating quality information to receptive or "vulnerable" subpopulations, and (5) evaluate the impact of this program by randomizing numbers of a large purchasing organization to receive existing quality information with or without this supplemental program. This study will be organized into two phases. Phase I will be an observational study linked to the open enrollment (OE) period of a major California purchasing organization in fall 2001. A stratified random sample of members will be selected, with oversampling of members who are more likely to switch health plans (based on demographic characteristics). A pre-OE written current plan and medical group, likelihood of switching, predisposition and intent to use quality information, and previous behaviors related to plan choice. An immediately post-OE survey of the same respondents will address actual decisions (and reasons), current knowledge, actual use of information from different sources (and reasons), and strengths and limitations of available information. An overlapping group of members, boosted by additional members who switched plans, will be surveyed by telephone and in focus groups 9 months later to assess subsequent use of quality information, satisfaction with the chosen plan and medical group, and intervention, linked to the same organization's fall 2002 OE period. The design of this intervention will be based partially on the age, gender, and health characteristics; personalized portals to facilitate access to relevant Internet resources; and an "active consumer" educational/motivational program. Measures of impact will include health plan or medical group switching (or contemplation thereof), knowledge of the health car market, satisfaction with current plan and medical group, trust or confidence in the plan and physician, and self-efficacy related to health plan and provider interactions.